Rhythm Pharmaceuticals Bets Big On Obesity Growth

Rhythm Pharmaceuticals ((RYTM)) has held its Q1 earnings call. Read on for the main highlights of the call.

Rhythm Pharmaceuticals’ latest earnings call struck a cautiously upbeat tone, with management emphasizing steady commercial growth, rapid international momentum and major regulatory wins for its obesity drug IMCIVREE. Executives acknowledged rising expenses and continued GAAP losses but argued that a strong cash position and expanding patient base position the company well despite near-term volatility in payers and inventory patterns.

Global Revenue Growth and U.S. Contribution

Rhythm reported Q1 2026 global net revenue of $60.1 million, up 5% sequentially from $57 million in Q4 2025, underscoring steady but not explosive growth. The U.S. remained the company’s revenue engine, accounting for 61% of sales, though management highlighted increasing diversification as ex‑U.S. markets ramp.

International Sales Acceleration

Outside the U.S., revenue jumped from $18.3 million to $23.2 million in Q1, a strong 27% sequential increase driven by higher volumes in Germany and France. Additional demand from named‑patient markets such as Saudi Arabia and Greece further reinforced the view that international adoption is gaining meaningful traction.

Rising Number of Reimbursed Patients

Globally, the number of patients on reimbursed therapy rose 8% quarter over quarter, reflecting expanding real-world use of IMCIVREE. Growth was led by Bardet‑Biedl syndrome patients and participants in international early access programs, signaling a broader and increasingly durable treatment base.

Early Momentum in Hypothalamic Obesity Launch

The newly approved hypothalamic obesity indication showed encouraging early demand, with more than 150 start forms received in the first six weeks post‑U.S. approval. About 110 unique prescribers have already written scripts, roughly 80% new to IMCIVREE and predominantly endocrinologists, as the salesforce scaled from 16 to 42 reps to pursue an estimated 10,000‑patient opportunity across the U.S. and Europe.

Key Regulatory Wins and Market Access Progress

The U.S. FDA approval for acquired hypothalamic obesity on March 19, followed quickly by European Commission marketing authorization, marked major strategic milestones. In Japan, the PMDA has accepted the company’s NDA, with management anticipating potential approval and launch by the end of 2026 and broader EU country launches targeted beginning in 2027.

Real‑World Evidence and Early Access Data

Early access programs in France and Italy have delivered both revenue and valuable real‑world experience in treated patients. Notably, France’s AP1 program generated data from more than 60 hypothalamic obesity patients, including up to 12 months on therapy, with results slated for presentation at the European Congress of Endocrinology to support physician confidence and payer discussions.

Cash Position and Operating Runway

The company ended Q1 with approximately $341 million in cash, cash equivalents and short‑term investments, which management believes will fund planned operations for at least 24 months. This liquidity cushion provides room to invest in launches, trials and manufacturing scale‑up while absorbing current operating losses.

Pipeline Progress and Upcoming Milestones

Management reiterated that key clinical and development programs remain on track, with near‑term milestones including six‑month Prader‑Willi syndrome data from Dr. Miller at Endo in June and midyear readouts for RM‑718. Part C hypothalamic obesity results are targeted for the Q2 call, and chemistry, manufacturing and controls work is advancing toward a Phase III start for bivamelagon in hypothalamic obesity by year‑end 2026.

GAAP Losses and Cash Burn Dynamics

Despite top‑line progress, Rhythm posted a GAAP net loss per share of $0.83 in Q1 2026, underscoring the cost of scaling its commercial and R&D platforms. Cash used in operations was approximately $44.2 million for the quarter, reflecting both expanding infrastructure and elevated investment in future growth drivers.

Sharp Increase in SG&A Spending

Selling, general and administrative expenses climbed to $63.6 million in Q1 2026 from $39.1 million a year earlier, a hefty 62.7% year‑over‑year jump. Management attributed the rise to higher headcount, stock‑based compensation and marketing initiatives tied to the hypothalamic obesity launch, all aimed at driving broader physician adoption.

R&D Investment Trend

Research and development spending also moved higher, reaching $41.7 million versus $37.0 million in the prior‑year quarter, a roughly 12.7% increase. The company cited higher personnel costs as the primary driver, as it advances multiple programs and prepares pivotal‑stage work for its next‑generation obesity candidate.

Revenue Variability and Inventory Effects

Management flagged that short‑term revenue can be distorted by specialty pharmacy inventory movements, including a roughly $1.8 million inventory build in Q4 that shifted timing across quarters. Named‑patient markets, which order with variable lead times, add another layer of quarter‑to‑quarter variability that investors should consider when assessing near‑term trends.

Payer Policy Timing and Reimbursement Risk

While early payer responses and initial approvals for the new hypothalamic obesity indication have been positive, the company expects HO‑specific coverage policies to take roughly three to nine months to firm up. This lag creates near‑term uncertainty around payer mix and net realized price per patient, even as underlying demand appears robust.

Gradual Conversion in Early Launch Dynamics

Most prescribers have written only a single prescription so far, suggesting that broader uptake will build over time rather than spike immediately. Management noted that conversion beyond clinical trial patients depends on how frequently patients see physicians and ongoing education of health care providers, pointing to a steady rather than abrupt adoption curve.

Japanese Cohort Efficacy Nuances

The company discussed modestly lower placebo‑adjusted BMI differences in the Japanese cohort compared with the overall 142‑patient population, as placebo patients in Japan did not gain weight like Western controls. With relatively small sample sizes and potential cultural influences, management acknowledged some uncertainty but maintained confidence in the broader efficacy profile.

Guidance and Outlook

Rhythm reaffirmed 2026 non‑GAAP operating expense guidance of $385 million to $415 million, split between $197 million to $213 million for R&D and $188 million to $202 million for SG&A, with expenses expected to rise as manufacturing and clinical supply investments ramp. The company highlighted Q1’s 5% sequential revenue growth, 27% international surge, expanding reimbursed patient base and a roadmap that includes payer policy rollout over the next several months, staged EU and Japan launches and the planned start of a Phase III bivamelagon trial by the end of 2026.

Rhythm’s call painted a picture of a company leaning into growth, trading near‑term losses and spending for a larger global obesity opportunity anchored by IMCIVREE. For investors, the key watchpoints will be payer coverage timelines, international launch execution and delivery on clinical milestones, all against the backdrop of a solid balance sheet and strengthening commercial momentum.